This invention relates generally to indicators or monitors for recording maximum or peak pressures in a fluid system. More particularly, this invention relates to a pressure indicator of a compact form which records maximum pressure by means of a measurable deformation.
A number of devices and methods have been advanced for recording a maximum pressure in a fluid system. Strain gages, piezoelectric transducers and other instruments have been employed to record the maximum pressure in a fluid system. Such prior devices often require relatively large amounts of space and tend to be subject to a number of physical and dimensional constraints.
U.S. Pat. No. 3,345,876 entitled "High Pressure Indicator" discloses a pressure indicating apparatus which comprises a body member forming a conically shaped recess. A disc member is permanently deformed by being drawn into the recess when subjected to pressures above a pre-established threshold to thereby record the maximum pressure exerted against the disc. The deformation is a function of the pressure differential between the pressure in the recess and the external pressure. The drawing deformation involves a frictional engagement between the disc and the recess walls. The manufacturing of a highly accurate and reliable indicator of the type disclosed in U.S. Pat. No. 3,345,876 can be problematical due to the difficulties in replicating the frictional engagement during deformation. The high pressure indicator of U.S. Pat. No. 3,345,876 is employed for measuring moderately high peak pressures of short duration as commonly produced in gun barrels during firing. A high degree of sealing integrity between the deformable member and the recess is ordinarily not required for the short duration high pressure pulse application.